Edit: Oh damn this *IS* that video but WG EU is slow yet again making an article 7 days later.

So as above, idiotic checkpoint system (where most of your tank can be sticking out of cover as long as you hide certain bits you still won't get spotted even at point blank range) combined with barrel spotting is all you need to know.

You should add those videos in the game, or even in a launcher. Game Mode > Tutorial > Game mechanics. Players with less than 1,000 battles can get some gold...like 300 in total for watching every video and saw like 90% of it, or maybe some tier 2-3 premium tank. Players with more than 1k battles can get some credits. It will encourage every player, good or bad, to watch it.
This video is really good, I knew the mechanics, but I watched it anyway to see how good it is. Big plus + WG, but now you have to find a way to encourage some players to watch it.

There are seven points which get you spotted and given they are front rear sides top of turret and gun mantle you have to pretty much cover the entire tank to not get spotted.

Nope, you only have to cover the actual spotting points. It only takes a tree or pole to cover the side and turret ones, then you need a small rock or bush to cover the front or back one, the ones on the far side don't count (though bizarrely you can spot tanks through other tanks).